Clinical and Genetic Features of Autosomal Dominant Alport Syndrome: A Cohort Study.

RATIONALE & OBJECTIVE: Alport syndrome is a common genetic kidney disease accounting for approximately 2% of patients receiving kidney replacement therapy (KRT). It is caused by pathogenic variants in the gene COL4A3, COL4A4, or COL4A5. The aim of this study was to evaluate the clinical and genetic spectrum of patients with autosomal dominant Alport syndrome (ADAS). STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 82 families (252 patients) with ADAS were studied. Clinical, genetic, laboratory, and pathology data were collected. OBSERVATIONS: A pathogenic DNA variant in COL4A3 was identified in 107 patients (35 families), whereas 133 harbored a pathogenic variant in COL4A4 (43 families). Digenic/complex inheritance was observed in 12 patients. Overall, the median kidney survival was 67 (95% CI, 58-73) years, without significant differences across sex (P=0.8), causative genes (P=0.6), or type of variant (P=0.9). Microhematuria was the most common kidney manifestation (92.1%), and extrarenal features were rare. Findings on kidney biopsies ranged from normal to focal segmental glomerulosclerosis. The slope of estimated glomerular filtration rate change was-1.46 (-1.66 to-1.26) mL/min/1.73m2 per year for the overall group, with no significant differences between ADAS genes (P=0.2). LIMITATIONS: The relatively small size of this series from a single country, potentially limiting generalizability. CONCLUSIONS: Patients with ADAS have a wide spectrum of clinical presentations, ranging from asymptomatic to kidney failure, a pattern not clearly related to the causative gene or type of variant. The diversity of ADAS phenotypes contributes to its underdiagnosis in clinical practice.

Alkaline Phosphatases in the Complex Chronic Kidney Disease-Mineral and Bone Disorders.

Alkaline phosphatases (APs) remove the phosphate (dephosphorylation) needed in multiple metabolic processes (from many molecules such as proteins, nucleotides, or pyrophosphate). Therefore, APs are important for bone mineralization but paradoxically they can also be deleterious for other processes, such as vascular calcification and the increasingly known cross-talk between bone and vessels. A proper balance between beneficial and harmful activities is further complicated in the context of chronic kidney disease (CKD). In this narrative review, we will briefly update the complexity of the enzyme, including its different isoforms such as the bone-specific alkaline phosphatase or the most recently discovered B1x. We will also analyze the correlations and potential discrepancies with parathyroid hormone and bone turnover and, most importantly, the valuable recent associations of AP's with cardiovascular disease and/or vascular calcification, and survival. Finally, a basic knowledge of the synthetic and degradation pathways of APs promises to open new therapeutic strategies for the treatment of the CKD-Mineral and Bone Disorder (CKD-MBD) in the near future, as well as for other processes such as sepsis, acute kidney injury, inflammation, endothelial dysfunction, metabolic syndrome or, in diabetes, cardiovascular complications. However, no studies have been done using APs as a primary therapeutic target for clinical outcomes, and therefore, AP's levels cannot yet be used alone as an isolated primary target in the treatment of CKD-MBD. Nonetheless, its diagnostic and prognostic potential should be underlined.

Low consumption of fruit and vegetables and risk of chronic disease: a review of the epidemiological evidence and temporal trends among Spanish graduates.

OBJECTIVE: To review the evidence on the association between fruit and vegetable (F&V) consumption and risk of chronic disease, and to assess trends in the prevalence of low F&V consumption. DESIGN: Systematic review and cross-sectional analyses of a Mediterranean cohort. SETTING: The Seguimiento University of Navarra (SUN) project (Spanish dynamic cohort of graduates). SUBJECTS: A systematic review of prospective studies aimed to assess the relationship between fruit and/or vegetables consumption and chronic disease incidence was conducted. We also assessed 18 457 university graduates (59·4 % women; mean age = 39 (sd 12) years) enrolled in a dynamic cohort with permanently open recruitment. Baseline data were collected between 1999 and 2010 using a validated 136-item FFQ. Four definitions for low F&V consumption were used (<400 g/d, <200 g/4184 kJ (1000 kcal) per d, ≤2 servings/d and ≤1 serving/d). Multivariate-adjusted cross-sectional associations between the prevalence of low F&V consumption and the year of recruitment were estimated. RESULTS: The systematic review found that a high F&V consumption is inversely associated with CVD incidence and mortality. This association is not so clear for cancer. Inconsistent findings have been reported for diabetes. In all, 13 % of participants in the SUN cohort did not meet the goal of consuming at least 400 g/d of F&V and 2·1 % of them did not reach >1 serving/d. Between 1999 and 2010 the consumption of F&V significantly increased. CONCLUSIONS: Even among health-conscious university graduates, low F&V consumption is fairly prevalent. Although the temporal trends suggest an improvement, preventive strategies addressed to increase F&V consumption are needed.

The Impact of Age on Mortality in Chronic Haemodialysis Popu-Lation with COVID-19.

Age and chronic kidney disease have been described as mortality risk factors for coronavirus disease 2019 (COVID-19). Currently, an important percentage of patients in haemodialysis are elderly. Herein, we investigated the impact of age on mortality among haemodialysis patients with COVID-19. Data was obtained from the Spanish COVID-19 chronic kidney disease (CKD) Working Group Registry. From 18 March 2020 to 27 August 2020, 930 patients on haemodialysis affected by COVID-19 were included in the Registry. A total of 254 patients were under 65 years old and 676 were 65 years or older (elderly group). Mortality was 25.1% higher (95% CI: 22.2-28.0%) in the elderly as compared to the non-elderly group. Death from COVID-19 was increased 6.2-fold in haemodialysis patients as compared to the mortality in the general population in a similar time frame. In the multivariate Cox regression analysis, age (hazard ratio (HR) 1.59, 95% CI: 1.31-1.93), dyspnea at presentation (HR 1.51, 95% CI: 1.11-2.04), pneumonia (HR 1.74, 95% CI: 1.10-2.73) and admission to hospital (HR 4.00, 95% CI: 1.83-8.70) were identified as independent mortality risk factors in the elderly haemodialysis population. Treatment with glucocorticoids reduced the risk of death (HR 0.68, 95% CI: 0.48-0.96). In conclusion, mortality is dramatically increased in elderly haemodialysis patients with COVID-19. Our results suggest that this high risk population should be prioritized in terms of protection and vaccination.

Predictors of outcome in a Spanish cohort of patients with Fabry disease on enzyme replacement therapy.

Fabry disease may be treated by enzyme replacement therapy (ERT), but the impact of chronic kidney disease (CKD) on the response to therapy remains unclear. The aim of the present study was to analyse the incidence and predictors of clinical events in patients on ERT. STUDY DESIGN: Multicentre retrospective observational analysis of patients diagnosed and treated with ERT for Fabry disease. The primary outcome was the first renal, neurological or cardiological events or death during a follow-up of 60 months (24-120). RESULTS: In 69 patients (42 males, 27 females, mean age 44.6±13.7 years), at the end of follow-up, eGFR and the left ventricular septum thickness remained stable and the urinary albumin: creatinine ratio tended to decrease, but this decrease only approached significance in patients on agalsidase-beta (242-128mg/g (p=0.05). At the end of follow-up, 21 (30%) patients had suffered an incident clinical event: 6 renal, 2 neurological and 13 cardiological (including 3 deaths). Events were more frequent in patients with baseline eGFR≤60ml/min/1.73m2 (log Rank 12.423, p=0.001), and this remained significant even after excluding incident renal events (log Rank 4.086, p=0.043) and in males and in females. Lower baseline eGFR was associated with a 3- to 7-fold increase the risk of clinical events in different Cox models. CONCLUSIONS: GFR at the initiation of ERT is the main predictor of clinical events, both in males and in females, suggesting that start of ERT prior to the development of CKD is associated with better outcomes.

Predictors of outcome in a Spanish cohort of patients with Fabry disease on enzyme replacement therapy.

Fabry disease may be treated by enzyme replacement therapy (ERT), but the impact of chronic kidney disease (CKD) on the response to therapy remains unclear. The aim of the present study was to analyse the incidence and predictors of clinical events in patients on ERT. STUDY DESIGN: Multicentre retrospective observational analysis of patients diagnosed and treated with ERT for Fabry disease. The primary outcome was the first renal, neurological or cardiological events or death during a follow-up of 60 months (24-120). RESULTS: In 69 patients (42 males, 27 females, mean age 44.6±13.7 years), at the end of follow-up, eGFR and the left ventricular septum thickness remained stable and the urinary albumin: creatinine ratio tended to decrease, but this decrease only approached significance in patients on agalsidase-beta (242-128mg/g (p=0.05). At the end of follow-up, 21 (30%) patients had suffered an incident clinical event: 6 renal, 2 neurological and 13 cardiological (including 3 deaths). Events were more frequent in patients with baseline eGFR≤60ml/min/1.73m2 (log Rank 12.423, p=0.001), and this remained significant even after excluding incident renal events (log Rank 4.086, p=0.043) and in males and in females. Lower baseline eGFR was associated with a 3- to 7-fold increase the risk of clinical events in different Cox models. CONCLUSIONS: GFR at the initiation of ERT is the main predictor of clinical events, both in males and in females, suggesting that start of ERT prior to the development of CKD is associated with better outcomes.

Forward Genetic Screen Using Zebrafish to Identify New Genes Involved in Myelination.

Zebrafish are now well established as the preeminent vertebrate model with which to carry out gene discovery/forward genetic screens to identify the molecular genetic basis of biological processes. Gene discovery screens in zebrafish have already provided novel insight into mechanisms of glial cell development and function. The vast majority of genetic screens in zebrafish are based around a three generation screen that starts with the random induction of mutations in adult males using the chemical mutagen ENU. Here we outline the methods that underlie this type of screen, detailing each step, from ENU mutagenesis, through the breeding schemes required to recover homozygous mutant animals in subsequent generations, the screening procedure itself, with a focus on the analysis of myelinating glia, and the subsequent confirmation of mutant phenotypes.

Three cases of monoclonal gammopathy of renal significance after kidney transplantation. De novo C3 glomerulopathy. / Tres casos de gammapatía monoclonal de significado renal postrasplante renal: nefropatía c3 de novo.

Monoclonal gammopathy of renal significance includes all renal disorders caused by a monoclonal immunoglobulin secreted by a non-malignant B-cell clone. Patients with MGRS do not, by definition, meet criteria for multiple myeloma, with haematological disorders generally considered to be monoclonal gammopathy of undetermined significance. Nevertheless, the renal involvement can be serious and require specific treatment. Monoclonal gammopathy of renal significance is associated with a wide spectrum of disorders, including the recently discovered C3 glomerulopathy. Development of C3 glomerulopathy in the context of monoclonal gammopathy of renal significance after kidney transplantation is uncommon and very few cases have been published to date. We report on three cases of C3 glomerulopathy in the context of de novo monoclonal gammopathy after kidney transplantation.

Osteoporosis, bone mineral density and CKD-MBD (II): Therapeutic implications. / Osteoporosis, densidad mineral ósea y complejo CKD-MBD (II): implicaciones terapéuticas.

Osteoporosis (OP) and chronic kidney disease (CKD) both independently affect bone health. A significant number of patients with CKD have decreased bone mineral density (BMD), are at high risk of fragility fractures and have an increased morbidity and mortality risk. With an ageing population, these observations are not only dependent on "renal osteodystrophy" but also on the associated OP. As BMD predicts incident fractures in CKD patients (partI), we now aim to analyse the potential therapeutic consequences. Post-hoc analyses of randomised studies have shown that the efficacy of drugs such as alendronate, risedronate, raloxifene, teriparatide and denosumab is similar to that of the general population in patients with a mild/moderate decline in their glomerular filtration rate (especially CKD-3). These studies have some flaws however, as they included mostly "healthy" women with no known diagnosis of CKD and generally with normal lab test results. Nevertheless, there are also some positive preliminary data in more advanced stages (CKD-4), even though in CKD-5D they are more limited. Therefore, at least in the absence of significant mineral metabolism disorders (i.e. severe hyperparathyroidism), the potential benefit of these drugs should be considered in patients with a high or very high fracture risk. It is an important change that the new guidelines do not make it a requirement to first perform a bone biopsy and that the risk/benefit ratio of these drugs may be justified. However, we must also be aware that most studies are not consistent and the level of evidence is low. Consequently, any pharmacological intervention (risk/benefit) should be prudent and individualised.

Validity of a self-reported diagnosis of depression among participants in a cohort study using the Structured Clinical Interview for DSM-IV (SCID-I).

BACKGROUND: Depression assessment in population studies is usually based on depressive symptoms scales. However, the use of scales could lead to the choice of an arbitrary cut-off point depending on the sample characteristics and on the patient diagnosis. Thus, the use of a medical diagnosis of depression could be a more appropriate approach. OBJECTIVE: To validate a self-reported physician diagnosis of depression using the Structured Clinical Interview for DSM-IV (SCID-I) as Gold Standard and to assess the factors associated to a valid self-reported diagnosis. METHODS: The SUN Project is a cohort study based on university graduates followed-up through postal questionnaires. The response to the question included in the questionnaire: Have you ever been diagnosed of depression by a physician? was compared to that obtained through the SCID-I applied by a psychiatrist or a clinical psychologist. The percentages of confirmed depression and non-depression were assessed for the overall sample and according to several characteristics. Logistic regression models were fitted to ascertain the association between different factors and a correct classification regarding depression status. RESULTS: The percentage of confirmed depression was 74.2%; 95% confidence interval (95% CI) = 63.3-85.1. Out of 42 participants who did not report a depression diagnosis in the questionnaire, 34 were free of the disease (%confirmed non-depression = 81.1%; 95% CI = 69.1-92.9). The probability of being a true positive was higher among ex-smokers and non-smokers and among those overweight or obese but the differences were not statistically significant. CONCLUSION: The validity of a self-reported diagnosis of depression in the SUN cohort is adequate. Thus, this question about depression diagnosis could be used in further investigations regarding this disease in this graduate cohort study.

Osteoporosis, bone mineral density and CKD-MBD complex (I): Diagnostic considerations. / Osteoporosis, densidad mineral ósea y complejo CKD-MBD (I): consideraciones diagnósticas.

Osteoporosis (OP) and chronic kidney disease (CKD) independently influence bone and cardiovascular health. A considerable number of patients with CKD, especially those with stages 3a to 5D, have a significantly reduced bone mineral density leading to a high risk of fracture and a significant increase in associated morbidity and mortality. Independently of classic OP related to age and/or gender, the mechanical properties of bone are also affected by inherent risk factors for CKD ("uraemic OP"). In the first part of this review, we will analyse the general concepts regarding bone mineral density, OP and fractures, which have been largely undervalued until now by nephrologists due to the lack of evidence and diagnostic difficulties in the context of CKD. It has now been proven that a reduced bone mineral density is highly predictive of fracture risk in CKD patients, although it does not allow a distinction to be made between the causes which generate it (hyperparathyroidism, adynamic bone disease and/or senile osteoporosis, etc.). Therefore, in the second part, we will analyse the therapeutic indications in different CKD stages. In any case, the individual assessment of factors which represent a higher or lower risk of fracture, the quantification of this risk (i.e. using tools such as FRAX®) and the potential indications for densitometry in patients with CKD could represent an important first step pending new clinical guidelines based on randomised studies which do not exclude CKD patients, all the while avoiding therapeutic nihilism in an area of growing importance.

Osteoporosis, bone mineral density and CKD-MBD: treatment considerations.

Osteoporosis and chronic kidney disease (CKD) have both independently important potential impact on bone health. A significant number of patients with CKD stages 3a-5D have been shown to have low bone mineral density (BMD), leading to a strikingly elevated risk of fractures (mainly hip fractures) and higher associated morbidity and mortality. Mechanical properties of bone beyond age and menopausal status are additionally affected by intrinsic uremic factors. Therefore, we review in this article not only general concepts of osteoporosis and related consequences, but also the diagnostic and therapeutic implications of low BMD and bone fractures in CKD, beyond increased vascular calcification. Antiresorptive agents (mainly bisphosphonates) were not previously recommended when the estimated glomerular filtration rate (GFR) was lower than 30 ml/min/1.73 m2. However, post-hoc analysis of large randomized clinical trials found that these drugs (i.e. alendronate, ribandronate, denosumab) had comparable efficacy in improving BMD and reducing fracture risk in individuals (mainly women) with moderate reductions of GFR (mostly CKD stages 3-4). Therefore, at least in the absence of clear abnormalities of CKD-related mineral metabolism disturbances, bone antiresorptive agents (and maybe anabolic agents) that are or will be approved for general osteoporosis may be appropriate for CKD. Nephrologists should probably not ignore any longer fracture risk assessment, especially in patients with additional risk factors for osteoporosis if results will impact treatment decisions. However, although different therapeutic agents have been shown to reduce the risk of fracture in CKD patients with low BMD, specific prospective studies, with or without bone biopsies, in CKD are urgently needed.